Combines fast combines

[Farm_Kid2]

I doubt you can get much faster than a 2388 with the 2 speed hydro. But, you have to unhook the switch down on the transmission so that it will engage in 3rd gear. I don't know how fast it will go, but I think it would be faster than is safe for any combine, unless perhaps you are in the middle of Australia with flat roads and zero car trafficIJ

 

[shellman]

Do that and you will overheat the hydraulic oil because you will be dumping over the relief valves, not to mention being unsafe.

 

[djack]

In my experience, the Gleaners go down the road the fastest. All my Gleaners would travel 22-23 mph. I've barely seen 20 on axial flows and my New Hollands seem to run in the 18 mgh range. The JD's I've run seem to go about 20, but have not run the new STS's.

 

[riceman]

9790 Massey with 710x38 duals will run 25 and change.

 

[Marv]

Why is it unsafe to run 21 mph with the two speed hydro with the third gear lockout disengaged, but it was okay for my single speed hydro with 18.4 X 38 duals to run 20 mphIJ That's not much difference in speed. I'm not challenging, just asking. Also, why does the relief valve open when it only runs 3 or 4 mph faster in third with the lockout disengagedIJ Is it that close to the limits of system pressures in high gearIJ

 

[shellman]

let me try and answer both questions. On my 2188 the third gear lockout was bypassed when I purchased the machine. low side gave about 19 MPH on the a post. Shifting to high brought me close to 25 MPH only when the ground was level. Any type of incline and you would drop below 20. Engine high idle was on spec and no power complain problems. Hydro drive pressure was about 6700 psi so the relif valves were ok and the foot and inch valve was lifted all the way. So the decrease in speed could have only been one thing and that was a leak in the drive system over the reliefs. The real danger comes when trying to stop or even steer with a head on. When you go to the high side of the 2 speed you are decreasing the volume of the hydro drive motor. In doing so you are getting the increase in speed, but in order to propel the combine the hydraulic drive pressure increases. The hydrdo pump and motor are not of equal volumes.. Same thing occurrs when you change a driven sprocket from a larger to a smaller size. In do ing so you increase the rpm of the output shaft, but dedcrease the amount of torque you are capable of unless you increase the input. In the hydro case the drive pressure goes up resulting in HEAT. This is also the reason that it is recommended that any time you are in the field and have a pga you engage it. Now the reverse occurrs. I have increased the volume of the driven members and get a corresponding decrease in ground speed given the hydro control stays in the same position. Hydraulic drive pressure is also lower thus hydraulic oil temp also decreases. Hope this helps.

 

[hooter]

Have been bending the lock out wire on case combines for 14 years here in Oz and never had a problem with a hydro. We run from one end of the eastern wheat area to the other, about 1200 miles and do it all at 24-25 mph in high range